A mathematical method to analyze a model of common disease inheritance using marker genes wilt be work out. It consists in forming (1) a set of hypotheses about the mode of inheritance of a human trait (disease predisposition) and its connection with marker loci, and (2) a set of statistics or non-statistical characteristics to reveal any deficiency of a hypothesis. If a hypothesis is "compromised", it is to be rejected, reducing a set of rival hypotheses and of inheritance mechanisms. Recurrence risks will be calculated based on parameters estimated. Pedigrees will be used as data to estimate model parameters by the method of maximum likelihood.